RF Circuits and Systems - RF Transmitter Architectures

A radio-frequency transceiver comprising a receiver and a transmitter is the main system responsible for establishing communication between users of the communication system. This lecture focuses on the study and design of radio-frequency transmitters. The course starts with an overview of an RF transmitter and important design challenges in designing these systems.  The course then will provide an in-depth study of wireless transmitters. Starting with the problem of in-phase/quadrature (I/Q) mismatch and its impact on the transmitter performance, the course teaches a technique based on the detection of the signal mirror to calibrate the mismatch. The course then will go over another problem commonly seen in RF transmitters, which the carrier leakage. The students will learn that carrier leakage will disturb the signal constellation. Next, the important issue of the power amplifier and transmitter linearity will be studied. The students will learn the reason for the power-amplifier back-off to avoid EVM degradation. Next, the problem of local-oscillator pulling will be studied. Methods of combating the oscillator pulling in an RF transmitter. An overview of alternative transmitter structures including the direct conversion transmitter with LO working at twice the RF frequency, heterodyne, dual upconversion, and sliding IF transmitters will be introduced.